Antidepressant-like effect of lemon essential oil is through a modulation in the levels of norepinephrine, dopamine, and serotonin in mice: Use of the tail suspension test

Lemon is widely consumed in the diet, but limited reports are available on lemon essential oil (LEO) as a functional food ingredient. Though some studies have focused on the effects of LEO inhalation on depression, very few studies have investigated the oral administration of LEO. In this study, the antidepressant effects of orally administered LEO were evaluated in mice by tail suspension test (TST) and their influence on the brain monoamines was determined. Our findings revealed that none of the LEO concentrations tested (200-1600. mg/kg) affected the spontaneous locomotor activity or elicited physiological/histopathological changes in mice. Compared with fluoxetine (18. mg/kg, p.o.) as a positive control, 400. mg/kg LEO effectively reduced immobility time in the TST-subjected mice. HPLC analysis indicated that LEO-gavaged mice had significant differences in the concentrations of norepinephrine, dopamine, and serotonin in the prefrontal cortex, striatum, and hippocampus, which might, at least in part, account for the antidepressant effect of LEO.